Vacuum method for producing 25CrMnB steel

Abstract

The invention discloses a vacuum method for producing 25CrMnB steel, belongs to the field of ferrous metallurgy, and provides a method for producing the 25CrMnB steel. In the method, a small continuous casting machine can smoothly cast the steel. The method comprises the following steps of: (a) smelting by using a converter; (b) during tapping, adding calcium carbide to ensure that the oxygen activity in molten steel is below 0.0025 percent, and adding chrome iron to ensure that the chromium content is 0.30-0.60 percent; (c) adding 3.5 to 4.5kg of calcium carbide into each ton of molten steel before refining heating, and adding 0.15 to 0.45kg of aluminum metal into each ton of molten steel in the heating process; (d) in the vacuum cycle treatment, adding aluminum to ensure that the aluminum content is 0.011 to 0.016 percent, adding ferrotitanium to ensure that the titanium content is 0.02 to 0.06 percent, and adding ferroboron to ensure that the boron content is 0.0005 to 0.003 percent; and (e) continuously casting. The method is suitable for large continuous casting machines and can ensure that small continuous casting machines can smoothly cast the steel.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, and in particular relates to a method for producing 25CrMnB steel by a vacuum method. Background technique [0002] A small amount of boron (about 0.001%) can be adsorbed on the austenite grain boundary, reduce the grain boundary energy, inhibit the formation of ferrite nuclei, and double the hardenability of medium and low carbon steels. Therefore, medium and low carbon steels often Add 0.0005-0.003% trace amount of boron to improve hardenability of steel. However, boron is one of the most active elements, which can form stable inclusions with residual oxygen and nitrogen in steel, and lose its beneficial effect. Only boron in solid solution can play a beneficial role. [0003] Existing studies have shown that boron has a strong affinity with oxygen and nitrogen, and boron is easily oxidized to generate B 6 O or B 2 o 3 , or combined with nitrogen to form BN, these are harmful substa...

AI Technical Summary

Problems solved by technology

Specifically, molten steel with more than 0.02% aluminum or acid-soluble aluminum will produce a certain amount of Al in the casting process 2 o 3 , these Al 2 o 3 It will make the mold nozzle of the continuous casting machine smaller, which will affect the continuous casting, and even block the mold nozzle of the continuous casting machine, especially on the continuous casting machine with a cross-section of 200×200mm or below 200×200mm, making the small-sized continuous casting machine unable to cast